Hello Eugene, I am looking similar thing,
Do u have any luck or further information on your topic ? I am also looking for a way to apply global audio effect to system wide audio out. Let me know or reply here with further information. Thanks in advance. jrc On Thursday, June 30, 2011 7:15:35 AM UTC+5:30, eugene wrote: > > Following up from a previous thread "AudioEffect integration" > > Does anyone know the/a preferred way for an application to apply an > effect to the global output mix, and for the effect to remain applied > persistently (i.e. until removed). > On first thought I assume that the application that created the global > effect needs to remain alive. > > In my testing I've noticed that when my Java app exits, the global > effect successfully continues to process audio playing on the device, > but I notice in the process list (in the Eclipse Devices tab) that my > application is still running. I understand this is not the Java > application, but the linux/C process that is still running. > > If I manually [stop] this process, my global effect ceases (I can no > longer hear the effects of its processing). Therefore I assume that > this could also have occured if my process was killed by the system to > recover resources later on. > > So my question is: Would I need to ensure my application continues to > run (e.g. using a background service) so that the effect (or the > process responsible for it) does not get cleaned up? > > > > > On Jan 22, 4:29 am, Eric Laurent <elaur...@android.com> wrote: > > Hi, > > > > There is no other documentation onaudioeffects framework than the > > java doc for APIs > > and the comments in EffectApi.h foreffectengine implementers. > > > > You are almost correct when saying that "effects are applied either > > per-track before mixing, or on the output mix". > > The exact statement would be that "INSERT effects are applied either > > perAUDIOSESSION before mixing, or on the output mix". > > With the exception ofaudiosession 0 which by convention refers to > > the output mix, anaudiosession refers to either an AudioTrack or a > > group of > > AudioTracks. An inserteffectcreated on a particular session applies > > to all AudioTracks in that session. > > Now the AUXILIARY effects (currently only the Reverb when attached to > > output mix - session 0) are handled differently. An Auxiliaryeffect > > will process several inputs from AudioTracks (or MediaPlayers) and > > accumulate the result to the output mix. When the auxiliaryeffectis > > created, it will not process anything by default. An AudioTrack must > > be explicitly sent to the theeffectwith the attachAuxEffect > > method(). Then the amount of signal sent to theeffectis modified by > > the > > setAuxEffectSendLevel() method. This means that the AudioTrack has a > > WET path (going though theeffect) and a DRY path going directly to > > the output mix. So, yes, although instantiated on the session 0 > > (output mix), auxiliary effects do not > > apply equally to all sources. > > > > The statement "sameeffectengine being used multiple times" means > > that INSIDE A GIVENAUDIOSESSION, the sameeffectengine is reused if > > 2 applications create 2 instances of a the sameeffecttype. > > > > There is no built-in mechanism in the framework to ensure that effects > > applied in different sessions do not conflict with each other. > > However, currenteffectlibrary implementation has an optimized > > processing when multiple effects are applied within the same session. > > It is up to to the implementor of platform specificeffectlibraries > > that would replace the default ones to add this type of optimizations. > > > > A similar reply applies to your last question. Theeffectengines are > > notified by theeffectframeworks ofaudiodevice changes. It is up to > > the implementor to alter the process according to the type of device > > or devices connected. > > For instance, current virtualizer implementation behaves differently > > whether headphones are connected or not. > > > > Hope this helps. > > > > Eric. > > > > > per-track before mixing, or on the output mix > > > > On Jan 20, 2:55 pm, eugene <eugene.ar...@dolby.com> wrote: > > > > > > > > > > > > > > > > > Hi > > > I'm looking to add some new AudioEffects into the framework and also > > > get a good understanding of the implementation architecture of the > > > AudioEffects framework. > > > I can't find any documentation about these. Is there any publicly > > > available that I've missed? > > > > > Specifically I'm not clear on how the Effects framework instantiates > > > effects when the sameeffectis applied to multiple tracks. Looking at > > > the AudioFlinger source code, it seems like effects are applied either > > > per-track before mixing, or on the output mix from the mixer. This all > > > makes sense, but the higher level APIs/Java API refers to: > > > * sameeffectengine being used multiple times > > > * CPU load limiting to allocate effects to particular users > > > * and some "connectMode" (EFFECT_INSERT or EFFECT_AUXILIARY), the > > > ultimate purpose/implementation of which I'm unsure. > > > In general, I'm not sure what this means for the implementation. > > > The documentation states that an EFFECT_AUXILIARYeffectmust be > > > created on the global output mix, but then implies that a media player > > > oraudiotrack will only be "fed into thiseffect" if they are > > > explicitly attached and a send-level is specified. How can aneffect > > > that is configured for session 0 (global output mix) end up not > > > applying to anaudiotrack from an application? Does it get mixed > > > seperately inAudioFlinger? > > > > > Also, is there a way to enforce that effects don't end up conflicting > > > with eachother? e.g. Bass enhancement applying on anAudioTrack and a > > > Bass enhancementeffecton the global output mix. > > > > > Finally, what doAudioEffectimplementations need to consider for the > > > case that the output device is transitioning from one to another (e.g. > > > speaker to bluetooth headset), or when 2 output devices are being used > > > at the same time (e.g. when ringtone plays it can play over speaker > > > and bluetooth headset simultaneously). > > > > > Thanks > > > Eugene -- -- unsubscribe: android-porting+unsubscr...@googlegroups.com website: http://groups.google.com/group/android-porting --- You received this message because you are subscribed to the Google Groups "android-porting" group. To unsubscribe from this group and stop receiving emails from it, send an email to android-porting+unsubscr...@googlegroups.com. 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